The conventional fuse is used to electronic products. If the current past is too large, the fused portion will fuse so as to prevent the circuit to short-circuit. Moreover, with the requirement of compact size and light weight of the electronic products, more and more parts are necessary and more and more elements must be installed on the circuit board. The wires on the boards become more and more small-sized. The circuit protection also has a trend of small size and high rated current and thus the effect of electric arc can not be prevented.
Moreover, some fuses are made integrally. Referring to FIG. 1, a prior art fuse is illustrated, which is illustrated in U.S. Pat. No. 6,034,589 and applied to a surface mounting fuse chip 100, wherein a plurality of layers and fuses are used. In U.S. Pat. No. 7,268,661, a protection element of large current is disclosed, in that the material of the fuse and electric arc preventing material are discussed. In U.S. Pat. No. 5,726,621, a ceramic material with surface mounting protection circuit is disclosed. The structure and process of the fuse is disclosed. The current technology uses integral forming method. The fuses are limited by the uniformity of the ceramic powder and the temperature distribution in the fuse area so that the reliability is low.
The disadvantages of the prior art will be described herein. The fuse is formed integrally, the uniformity of ceramic powders used will affect the temperature distribution thereof so that the reliability is bad and it is not safe. The current fuse has a large size and a small rated current so that it is not suitable for the trend of compact size and light weight. Thus it can not match the requirement of market. The current fuse has a multilayer structure with a large resistance. The manufacturing process is complicated with a high cost and more material used. The yield ratio is low. The electric arc from the prior art fuse will affect the safety of the circuit, even an expensive device will be destroyed or burnt.